No. 12. PROFESSIONAL PAPERS OF THE CORPS OF ENGINEERS OF THE UNITED STATES ARMY. PUBLISHED BY AUTHORITY OF THE SECRETARY OF WAR. HEADQUARTERS CORPS OF ENGINEERS. (6. J. - Corpe of en Corps of engineers. H 1873.. USEFUL IN SURVEYING, GEODESY, AND PRACTICAL ASTRONOMY, INCLUDING ELEMENTS FOR THE PROJECTION OF MAPS, AND INSTRUCTIONS FOR FIELD MAGNETIC OBSERVATIONS. 26. s. - Coups of engincers (8) Third Edition, Revised and Enlarged. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1873. OFFICE OF THE CHIEF OF ENGINEERS, Washington, February 24, 1873. GENERAL: In preparing this third edition of a volume compiled in 1849 for the use of the Corps of Topographical Engineers, when an officer in that corps, I have made such additions and corrections as experience has suggested and the requirements of the service seemed to demand. Intended more especially for field-use by officers engaged in surveys or explorations, and aspiring to no further merit than that of accuracy, utility, and convenience, it is submitted with the hope that it may continue to be favorably received by those who may have occasion to refer to it. The revision was undertaken at the suggestion of others, and not without reluctance. I beg indulgence for its defects. Very respectfully, Brigadier-General A. A. HUMPHREYS, THOS. J. LEE. Chief of Engineers, United States Army. |